The majority of obstetric deliveries in the US undergo continuous electronic uterine activity monitoring. Typically, an external tocodynamometer (strain gauge) is employed to provide the frequency and timing of uterine contractions. In some patients, particularly the obese, the monitor fails to detect contractions consistently. In others the monitor requires frequent repositioning by the nursing staff. The only available alternative is an invasive intrauterine pressure catheter (IUPC), with its associated increased risk of infection. The obstetric suite is subject to the obesity pandemic in the US, and these women have an increased risk for labor problems, infections and other complications. The specific goal of the proposed research is to develop a reliable, non-invasive uterine activity monitor that is unaffected by obesity and requires less nursing intervention than the tocodynamometer. The end-product will be a "Smart EHG Cable", called the eToco that converts the electrical activity of the uterus (electrohysterogram or EHG) into uterine activity signals compatible with existing monitors. The eToco system will plug into the toco or IUP port of existing monitors and provide more robust and reliable contraction curves with less nursing intervention required and improved patient comfort. Phase I results indicate that the EHG can provide such a monitor with a simple four electrode array. The electrode array will be a single mesh with an adhesive backing for ease of placement. This project proposes the following specific aims: Aim 1: Build production-equivalent prototype toco-replacement EHG hardware, software, and electrode mesh - An electrode mesh/array will be designed and prototyped based on the optimal positioning found in Phase I. In addition, production-equivalent hardware and embedded software for the eToco system will be designed and built. To support FDA clearance, a quality system will be initiated during product design. Aim 2: Clinically evaluate the mesh EHG uterine activity monitor -All data will be collected to the standards of the FDA Good Clinical Practice (GCP) and will be sufficient to provide statistical significance. The clinical study is in two parts: the first will evaluate the system in 130 patients versus the toco and IUP and the second part will evaluate the interpretation of skilled clinicians on the three signals to ensure similarity. Aim 3: Preparation for submission of FDA 510(k) for toco-replacement system - all necessary quality control systems will be implemented during this project. In addition, the 510(k) submission will be prepared. Aim 4: Initial testing of an acoustic sensor for fetal heart rate monitoring - The next generation product will include a more reliable replacement for the ultrasound FHR sensor. A prototype acoustic sensor will be tested as a novel method for non-invasive monitoring of the fetal heart rate. PUBLIC HEALTH RELEVANCE: The current method of non-invasive monitoring of uterine activity fails frequently, particularly in the obese patient. When this occurs, often clinicians must use an invasive intra- uterine pressure catheter that is particularly problematic in these patients since they are already at increased risk for infections. The development of an alternative, inexpensive sensor replacement technology that allows for existing monitors to non-invasively monitor uterine activity will improve diagnostic data, reduce required nursing interventions, and reduce infectious complications by limiting the need for invasive monitoring.